Typical Progression and Management of Idiopathic Intracranial Hypertension (IIH)
IIH typically affects women of childbearing age with obesity, presenting with headache and papilledema, and requires a structured management approach focusing on treating the underlying disease, protecting vision, and minimizing headache disability. 1, 2
Clinical Presentation and Natural History
- IIH predominantly affects women with BMI >30 kg/m², with symptoms including progressively worsening headache, transient visual obscurations (darkening of vision lasting seconds), pulsatile tinnitus, visual blurring, and horizontal diplopia 1, 2
- Papilledema is the hallmark finding, though IIH without papilledema is a rare subtype 2
- Other symptoms may include dizziness, neck pain, back pain, cognitive disturbances, and radicular pain 2
- Long-term visual prognosis is generally excellent with appropriate management, though some patients (6.1%) with more severe disease require surgical intervention 3
Diagnostic Features
- Neuroimaging (MRI brain preferred, or CT if MRI unavailable) should be performed within 24 hours to exclude secondary causes 2
- CT or MR venography is mandatory to exclude cerebral sinus thrombosis 2
- Typical neuroimaging findings include empty or partially empty sella, increased optic nerve tortuosity, enlarged optic nerve sheath, flattened posterior globe/sclera, intraocular protrusion of optic nerve head, and transverse sinus stenosis 1
- Lumbar puncture confirms elevated opening pressure (>25 cm H₂O) with normal CSF composition 4
Management Principles
1. Treat the Underlying Disease
- Weight loss is the primary disease-modifying treatment for IIH 1
- Medically-directed weight loss or bariatric surgery may be considered as primary therapy for suitable candidates 5
2. Protect Vision
- When there is evidence of declining visual function, acute management to preserve vision is surgical 1
- A temporizing lumbar drain may protect vision while planning urgent surgical treatment 1
- Surgical options include:
- CSF diversion procedures (VP shunt preferred over LP shunt due to lower revision rates) 1
- Optic nerve sheath fenestration (ONSF) - particularly useful for asymmetric papilledema causing visual loss in one eye 1
- Venous sinus stenting - emerging treatment with promising results for suitable candidates 6, 7
3. Minimize Headache Disability
- Patients must be informed early about the risks of medication overuse headache 1
- Short-term analgesics may be helpful in the first few weeks following diagnosis, including NSAIDs or paracetamol 1
- Topiramate may have a role in IIH management with weekly dose escalation from 25 mg to 50 mg twice daily 1
- Women prescribed topiramate must be informed about reduced contraceptive efficacy and potential side effects including depression, cognitive slowing, and teratogenic risks 1
Medical Management
- Acetazolamide is commonly used as first-line treatment (86.4% of patients in one study), though 34.2% discontinued due to adverse events 3
- Serial lumbar punctures are not recommended for management of IIH 1
- Other diuretics such as furosemide, amiloride, and coamilofruse may be used as alternative therapies, though their role is less certain 1
Surgical Interventions
- VP shunts should be the preferred CSF diversion procedure for visual deterioration in IIH 1
- Neuronavigation should be used to place VP shunts 1
- Adjustable valves with antigravity or antisiphon devices should be considered to reduce the risk of low-pressure headaches 1
- ONSF has fewer complications than CSF diversion but is performed more frequently in Europe and the USA than in the UK 1
- Neurovascular stenting shows promise but its role is not yet fully established; long-term antithrombotic therapy is required for longer than 6 months following this procedure 1, 6
Prognosis and Follow-up
- Visual field measures and retinal nerve fiber layer thickness typically improve with appropriate treatment 3
- Treatment failure rates for surgical interventions include worsening vision after initial stabilization in 34% of patients at 1 year and 45% at 3 years 1
- Failure to improve headache occurs in one-third to one-half of surgically treated patients 1
- Regular follow-up with neuro-ophthalmology is essential to monitor for changes in papilledema and visual function 7